The present disclosure relates to a photodetector structure and a method of manufacturing the same, and more particularly, to a photodetector structure which can be integrated into a substrate together with a complementary metal-oxide semiconductor (CMOS) integrated circuit (IC), thereby being economical, and a method of manufacturing the same.
Conventionally, methods of growing single-crystals of germanium (Ge) on a single-crystalline silicon (Si) layer using a silicon-on-insulator (SOI) substrate are usually used to manufacture a photodetector which operates at a wavelength band from about 1.3 μm to about 1.5 μm on a Si substrate. Although Si and Ge are all group four elements, since the lattice constant of Ge is about 4% higher than that of Si, misfit dislocation may cause a lot of treading dislocation on a Ge layer. Treading dislocation is the major cause of increasing leakage current and dark current. Methods of performing chemical vapor deposition (CVD) on Ge at a lower temperature and then performing CVD again on Ge at a higher temperature or performing post heat-treatment on Ge are usually used to minimize treading dislocation.
However, there may be significant difficulties and costs associated with lowering treading dislocation density below standard due to the fundamental difference in lattice constant between two materials. Moreover, when the SOI substrate is used, it may not be economical since the SOI substrate may be expensive and the photodetector and CMOS ICs may not be integrated into one substrate.
Thus, there is a need in the art for a photodetector structure which lowers treading dislocation density below standard, can be integrated into one substrate together with a complementary metal-oxide semiconductor (CMOS) integrated circuit (IC), and is economical, and a method of manufacturing the same